The present invention relates to a controllable magnetic bearing apparatus and a method for determining a machine type of a magnetic bearing.
The controllable magnetic bearing apparatus consists of a machine body including a rolling element and magnetic bearings, and a control unit for controlling the machine body. There are plural types of machine bodies so that control parameters vary depending upon the machine types. Accordingly, there has been a need for providing each control unit in correspondence to each type of machine body.
In order to provide each control unit in correspondence to each type of machine body, multiple types of control units must be fabricated on a small-lot basis. This not only imposes inconvenience but also makes it impossible to reduce costs through mass production.
In view of the foregoing, the present invention has an object to provide a controllable magnetic bearing apparatus having a control unit applicable to multiple types of machine bodies. It is another object of the present invention to provide a method for determining a machine type to apply the control unit to any of the multiple types of machine bodies.
In accordance with the present invention, a controllable magnetic bearing apparatus sensing a position of a rolling element supported by a magnetic bearing and controlling the position thereof, the apparatus comprises: means for moving the rolling element in a stationary state in a predetermined direction to determine an amount of movement thereof to a movement limit; and means for determining a machine type of the magnetic bearing based on the amount of movement and setting control parameters (Claim 1).
In the controllable magnetic bearing apparatus thus arranged, the amount of movement of the rolling element is determined by moving the rolling element in a stationary state to the movement limit. The machine type is determined based on a fact that the amount of movement varies depending upon the machine types and then, the setting of control parameters is made. Accordingly, a common control unit can be applied to the multiple types of machine bodies.
In accordance with the present invention, a controllable magnetic bearing apparatus sensing a position of a rolling element supported by a magnetic bearing and controlling the position thereof, the apparatus comprises: means for moving the rolling element in a stationary state in plural directions to determine respective amounts of movement of the rolling element to respective movement limits; means for determining a mean amount of movement based on the amounts of movement; and means for determining a machine type of the magnetic bearing based on the mean amount of movement and setting control parameters (Claim 2).
In the controllable magnetic bearing apparatus thus arranged, determined is the mean amount of movement of the rolling element when the rolling element in a stationary state is moved to the movement limits in the plural directions. Subsequently, the machine type is determined based on a fact that the mean amount of movement varies with each machine type, so as to set the control parameters. Accordingly, a common control unit can be applied to multiple types of machine bodies. In addition, the determination of the machine type is highly reliable because the determination is based on the mean amount of movement.
In accordance with the present invention, a method for determining a machine type of a magnetic bearing comprises: the steps of moving a rolling element supported by a magnetic bearing from a rest position to place on one side of a first radial axis for determining an amount of movement thereof to a movement limit; then moving the rolling element to place on one side of a second radial axis for determining an amount of movement thereof to a movement limit; then moving the rolling element to place on the other side of the first radial axis for determining an amount of movement thereof to a movement limit; then moving the rolling element to place on the other side of the second radial axis for determining an amount of movement thereof to a movement limit; operating a mean amount of movement based on the amounts of movement; and determining a machine type of the magnetic bearing based on the mean amount of movement and setting control parameters (Claim 3).
In the method for determining the machine type of the magnetic bearing, the mean amount of movement is found from the amounts of movement of the rolling element, which, initially being in a stationary state, is sequentially moved to each of the movement limits in each of the different directions. The machine type is determined based on the fact that the mean amount of movement varies with each machine type. Then, the setting of control parameters is made. Accordingly, a common control unit can be applied to multiple types of machine bodies. The determination of the machine types is highly reliable because the determination is based on the mean amount of movement.